The sun pours down a lot of energy onto the surface of the ocean every day. Now scientists are figuring out a way to get that energy onto the grid, with only seawater as a waste product. It just requires a really, really long pipe.

In the latest installment of the Butterfly Effect: Predator drones are just the start of unmanned, autonomous warfare technology. But as the tech becomes more democratized and more deadly, what happens when anyone can assemble an army of killing machines?

Lockheed Martin, the giant defense contractor, is wary of letting its staff use social networking. It's probably something to do with secrecy. But it also knows its staff are people, so it's built its own social net, and is now releasing it open-source.

It's tough to judge the sustainability of defense contractors—after all, they deal in wartime equipment, which isn't exactly friendly to the planet or the people living on it. But two of the biggest contractors, Raytheon and Lockheed Martin, actually have a a lot going for them in the sustainability arena. In the new book The HIP Investor, author and investment adviser R. Paul Herman compares the two. We do the same here.